Aircraft fuselage section, aircraft fuselage and aircraft

Description

[0001] The invention relates to a fuselage section of an aircraft. The invention further relates to an aircraft fuselage and an aircraft having such a fuselage section or fuselage.

[0002] In future air travel carbon emissions should be reduced or avoided completely. There are two general propulsion systems that are considered. On the one hand electrically driven aircraft are considered. On the other hand, hydrogen is in principle considered a good option to completely remove carbon emissions. However, storage of hydrogen as a gas or liquid is not easy.

[0003] In the past some hydrogen demonstrators were constructed by adding a separate hydrogen tank in the cabin and air travel a single engine connected to said tank for testing.

[0004] US 3 951 362 A discloses a cryogenic fuel tank of a cylindrical design that has toroidal surface ends and is suspended in the aircraft structure.

[0005] GB 2 522 080 A discloses an aircraft with an air-breathing engine that is positioned at the rear of the aircraft with its intake receiving air after it has flowed over the aircraft fuel tank.

[0006] US 3 243 150 A discloses an aerospace vehicle using cryogenic propellants and having ist tank construction integrated with the aerospace vehicle structure.

[0007] US 2010 / 0 170 997 A1 discloses an aircraft including a fuselage including a cabin to accommodate persons, and a propulsion system. The propulsion system includes at least one tank, wherein part of the propulsion system can be used as an extension of the cabin to accommodate persons, the part of the propulsion system lying adjacent the cabin and separated from the cabin by a partition.

[0008] It is the objective of the invention to improve hydrogen tanks for aircraft.

[0009] The objective is achieved by the subject-matter of the independent claims. Preferred embodiments are subject-matter of the dependent claims.

[0010] The invention provides an aircraft fuselage of an aircraft, wherein the aircraft fuselage is divided into a passenger section and a tank section, wherein the tank section is disposed adjacent to the passenger section and the tank section comprises a liquid hydrogen tank adapted for storing liquid hydrogen, tank skin panels, tank stringers, tank frames, and a pressure bulkhead, wherein the liquid hydrogen tank has a tank wall that encloses a tank volume for storing the liquid hydrogen, characterized in that the tank wall is formed by the tank skin panels, tank stringers, tank frames, and the pressure bulkhead, wherein the tank stringers and the tank frames are disposed within the tank volume.

[0011] Preferably, the fuselage section comprises a second pressure bulkhead that is arranged spaced along a forward-aft direction from the pressure bulkhead, and the second pressure bulkhead is fixed to at least one tank skin panel.

[0012] Preferably, the pressure bulkhead is fixed to at least one tank skin panel. Preferably, the pressure bulkhead and / or the second pressure bulkhead are welded and / or riveted to at least one tank skin panel.

[0013] Preferably, the tank wall is strengthened such that it can withstand a tank pressure in the tank volume above 1 bar, preferably up to 5 bar, more preferably up to 3 bar.

[0014] Preferably, the liquid hydrogen tank comprises a refilling tube that fluidly connects the tank volume to an external connector that is arranged to receive a supply connector for refilling liquid hydrogen.

[0015] Preferably, the liquid hydrogen tank comprises an evacuation tube and a pressure regulation device that is configured for, when a tank pressure exceeds a predetermined pressure threshold, discharge hydrogen gas from the tank volume via the evacuation tube to the environment.

[0016] Preferably, the liquid hydrogen tank has a thermal insulation that is disposed on the tank wall.

[0017] Preferably, the fuselage section comprises an external protective skin that is disposed on the liquid hydrogen tank, so as to protect the liquid hydrogen tank from foreign objects impacting thereon.

[0018] Preferably, the a cabin pressure in the passenger section is lower than a tank pressure in the tank volume.

[0019] The invention provides an aircraft comprising a preferred fuselage section and / or a preferred aircraft fuselage, and at least one engine that is configured for operating with liquid hydrogen as a fuel, wherein the tank volume is fluidly connected to the engine, so as to enable fluid transport of hydrogen from the tank volume to the engine.

[0020] The idea is to create a fuselage structure having an integrated liquid hydrogen tank, made from stiffened metal or composite panels and pressure bulkheads, in which all joints are welded or riveted. This configuration can as well be adapted to fore- and aft tank concepts and basically any other configuration.

[0021] The skin, stringers and frames in the tank-section are preferably sized thicker than in the cabin-section, due to the higher internal pressure. Yet, overall the ideas presented herein save considerable weight compared with having a separate, non-structural liquid hydrogen tank inside the fuselage, with separate brackets and strengthened sections in the fuselage. In particular, the avoidance of a regular rear pressure bulkhead in the fuselage, and a separate, pressurized end-section of the liquid hydrogen tank, instead designed as one bulkhead, is able to save considerable space and weight.

[0022] Due to the integration into the fuselage, the inventive solution reduces not only weight but also manufacturing time and as a result costs. Compared to other solution, it is one of the lightest weight solutions. The liquid hydrogen tank preferably uses strengthened fuselage stiffened skin (panels) as pressure vessel. Preferably, there is only one pressure bulkhead between the passenger (PAX) section and the liquid hydrogen tank, which further contributes to weight reduction. With this idea, no separate brackets are needed to keep liquid hydrogen tank in place. It is also not necessary to have an extra structure for tank integration and support structure. The invention is made on the idea that the fuselage skin can act also as a liquid hydrogen (LH2) tank wall. The fuselage skin hence has the double function for flight load carrying and LH2 containment.

[0023] The LH2 tank is integrated into the fuselage and uses modified airframe fuselage skin panels and the rear pressure bulkhead as its tank wall. The LH2 tank can be externally insulated.

[0024] Embodiments of the invention are described in more detail with reference to the accompanying drawings. Therein: Fig. 1 depicts a longitudinal section of an aircraft fuselage according to the invention.

[0025] Fig. 1 partially depicts a longitudinal section of an aircraft 10. The aircraft 10 has an aircraft fuselage 12. The aircraft fuselage 12 is divided into a passenger section 14 and a tank section 16.

[0026] The passenger section 14 comprises the usual components such as skin panels 18, stringers 20, and frame 22. The passenger section 14 may comprise in a manner known per se a passenger door 24, a galley 26, and a floor 28. The floor 28, for example, has a plurality of floor panels 30 that are supported by cross beams 32. The cross beams 32 are in turn supported by floor support beams 34, which rest on skin panels 18. The passenger section 14 has a cabin pressure P cabin . Typical cabin pressure values are around 0.6 bar when in cruise flight or higher depending on the cruising altitude of the aircraft 10.

[0027] The tank section 16 is disposed adjacent to the passenger section 14. The tank section 16 comprises a liquid hydrogen tank 36 that is configured for storage of liquid hydrogen (LH2). The liquid hydrogen tank 36 has a tank wall 38 that encloses a tank volume 40, in which the LH2 is stored.

[0028] The tank section 16 comprises tank skin panels 42, tank stringers 44, and tank frames 46. The tank skin panels 42, the tank stringers 44, and the tank frames 46 partially form the tank wall 38 and may be strengthened compared to the corresponding parts of the passenger section 14. Preferably, the parts have a greater thickness. The tank skin panels 42, the tank stringers 44, and the tank frames 46 are strengthened such that a tank pressure P LH2 of up to 3 bar to 5 bar can be easily maintained in the tank volume 40.

[0029] The tank section 16 further comprises a pressure bulkhead 48. The pressure bulkhead 48 is welded and / or riveted to the tank skin panels 42. The pressure bulkhead 48 is arranged adjacent to the passenger section 14 and separates it from the tank section 16. In contrast to conventional pressure bulkheads, the pressure bulkhead 48 domes towards the passenger section 14 instead of away from it. The pressure bulkhead 48 also forms part of the tank wall 38.

[0030] The tank section 16 further comprises a second pressure bulkhead 50. The second pressure bulkhead 50 is arranged opposite the pressure bulkhead 48 along the forward-aft direction. The second pressure bulkhead 50 is arranged beneath the vertical tail plane 52, for example. The second pressure bulkhead 50 domes towards aft in the usual manner. The second pressure bulkhead 50 may be smaller in diameter than the pressure bulkhead 48.

[0031] The tank section 16 comprises an external connector 54 for connecting a fuel supply for refueling. The external connector 54 is disposed on one of the tank skin panels 42. The external connector 54 is fluidly connected to the tank volume 40 by a refilling tube 56.

[0032] Furthermore, the tank section 16 includes a pressure regulating device 58 that is configured to release hydrogen gas to the environment through an evacuation tube 60, when a predetermined threshold is exceeded by the tank pressure P LH2 . Here, the evacuation tube 60 is running through the vertical tail plane 52.

[0033] The tank section 16 may include a thermal insulation 62. The thermal insulation 62 is arranged on the tank skin panels 42 and / or the pressure bulkhead 48 and / or the second pressure bulkhead 50.

[0034] The tank section 16 preferably has an external protective skin 64. The external protective skin 64 is arranged on the tank wall 38, preferably on the thermal insulation 62. The external protective skin 64 prevents impact of foreign objects on the tank wall 38 or the thermal insulation 62, thereby reducing the risk of leaks.

[0035] In order to improve liquid hydrogen storage on aircraft (10), the invention proposes a liquid hydrogen tank (36) that is integrated into the fuselage (12) of the aircraft (10). At least one portion of the tank wall (38) is formed by specially adapted tank skin panels (42) and / or a pressure bulkhead (48). The parts forming the tank wall (38) are strengthened so as to contain a tank pressure (P LH2 ) of about 3 bar.List of reference signs:

[0036] 10aircraft 12fuselage 14passenger section 16tank section 18skin panel 20stringers 22frame 24passenger door 26galley 28floor 30floor panels 32cross beams 34floor support beams 36liquid hydrogen tank 38tank wall 40tank volume 42tank skin panel 44tank stringer 46tank frame 48pressure bulkhead 50second pressure bulkhead 52vertical tail plane 54external connector 56refilling tube 58pressure regulating device 60evacuation tube 62thermal insulation 64external protective skin P cabin cabin pressure P LH2 tank pressure

Claims

1. An aircraft fuselage (12) of an aircraft, wherein the aircraft fuselage (12) is divided into a passenger section (14) and a tank section (16), wherein the tank section (16) is disposed adjacent to the passenger section (14) and the tank section (16) comprises a liquid hydrogen tank (36) adapted for storing liquid hydrogen, tank skin panels (42), tank stringers (44), tank frames (46), and a pressure bulkhead (48) , wherein the liquid hydrogen tank (36) has a tank wall (38) that encloses a tank volume (40) for storing the liquid hydrogen, characterized in that the tank wall (38) is formed by the tank skin panels (42), tank stringers (44), tank frames (46), and the pressure bulkhead (48), wherein the tank stringers (44) and the tank frames (46) are disposed within the tank volume (40).

2. The aircraft fuselage (12) according to claim 1, characterized by a second pressure bulkhead (50) that is arranged spaced along a forward-aft direction from the pressure bulkhead (48), and the second pressure bulkhead (50) is fixed to at least one tank skin panel (42).

3. The aircraft fuselage (12) according to any of the preceding claims, characterized in that the tank wall (38) is strengthened such that it can withstand a tank pressure (PLH2) in the tank volume (40) above 1 bar, preferably up to 5 bar, more preferably up to 3 bar.

4. The aircraft fuselage (12) according to any of the preceding claims, characterized in that the liquid hydrogen tank (36) comprises a refilling tube (56) that fluidly connects the tank volume (40) to an external connector (54) that is arranged to receive a supply connector for refilling liquid hydrogen.

5. The aircraft fuselage (12) according to any of the preceding claims, characterized in that the liquid hydrogen tank (36) comprises an evacuation tube (60) and a pressure regulation device (58) that is configured for, when a tank pressure (PLH2) exceeds a predetermined pressure threshold, discharge hydrogen gas from the tank volume (40) via the evacuation tube (60) to the environment.

6. The aircraft fuselage (12) according to any of the preceding claims, characterized in that the liquid hydrogen tank (36) has a thermal insulation (62) that is disposed on the tank wall (38).

7. The aircraft fuselage (12) according to any of the preceding claims, characterized by an external protective skin (64) that is disposed on the liquid hydrogen tank (36), so as to protect the liquid hydrogen tank (36) from foreign objects impacting thereon.

8. The aircraft fuselage (12) according to any of the preceding claims, characterized in that a cabin pressure (Pcabin) in the passenger section (14) is lower than a tank pressure (PLH2) in the tank volume (40).

9. An aircraft (10) comprising an aircraft fuselage (12) according to any of the claims 1 to 8, and at least one engine that is configured for operating with liquid hydrogen as a fuel, wherein the tank volume (40) is fluidly connected to the engine, so as to enable fluid transport of hydrogen from the tank volume to the engine.